Brush holder assembly with cantilever spring contact means



Dec. 28, 1965 F. J. TERKOSKI 3,226,497

BRUSH HOLDER ASSEMBLY WITH CANTILEVER SPRING CONTACT MEANS Filed Feb. 19, 1962 2 Sheets-Sheet l 46 INVENTOK 3 6 FRANK J. TERKOS/(l H/S ATTORNEY Dec. 28, 1965 F. J. TERKOSKI BRUSH HOLDER ASSEMBLY WITH CANTILEVER SPRING CONTACT MEANS Filed Feb. 19, 1962 2 Sheets-Sheet 2 INVENTOR. F/PANA J TEE/(OS/(l United States Patent 3,226,497 BRUSH HOLDER ASSEMBLY WITH CANTILEVER SPRING CONTACT MEANS Frank J. Terkoski, Rochester, N.Y., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Feb. 19, 1962, Ser. No. 174,195 3 Claims. (Cl. 20011) This invention pertains to electric converters, and particularly to an improved transmitter for converting direct current to alternating current.

A converter for transforming direct current to double frequency three phase alternating current is disclosed in copending application Serial No. 174,198, filed of even date herewith in the name of Carpenter et a1. and assigned to the assignee of this invention, including a brush drum assembly which carries five brushes biased outwardly therefrom by five coil springs. This invention relates to an improved converter embodying a cantilever spring means for loading the brushes thereby eliminating several components of the brush drum assembly, and in addition, reducing the over-all length of the transmitter housing. Accordingly, among my objects are the provision of an improved electric transmitter for converting direct current to alternating current including a disc-type brush holder; the further provision of an electric transmitter including cantilever spring biased brushes; and the still further provision of a five brush electric converter embodying unitary spring means for supporting three brushes.

The aforementioned and other objects are accomplished in the present invention by utilizing an insulative disc as a brush holder, the disc being mechanically connected to a rotatable drive shaft and carrying five brushes. Four of the brushes are located adjacent the periphery of the disc for engagement with a multi-section commutator, whereas the fifth brush is substantially centrally located and engages a slip ring. Two diametrically opposed peripheral brushes and the center brush are supported by a unitary cantilever spring assembly where- .by these three brushes are electrically interconnected. The other pair of diametrically opposed brushes are carried by separate cantilever spring reeds, and are also electrically connected to the housing.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the present invention is clearly shown and wherein similar reference numerals depict similar parts throughout the several views.

In the drawings:

FIGURE 1 is a longitudinal View, partly in section and partly in elevation, of the improved electric transmitter.

FIGURE 2 is an enlarged fragmentary view, partly in section and partly in elevation, of a portion of the transmitter shown in FIGURE 1.

FIGURE 3 is a reduced scale view taken along line 3-3 of FIGURE 2.

FIGURE 4 is an end view taken in the direction of arrow 4 of FIGURE 2.

FIGURE 5 is a fragmentary sectional view taken along line 55 of FIGURE 4.

FIGURE 6 is a fragmentary sectional view taken along line 66 of FIGURE 2.

Referring to FIGURE 1, the electric transmitter comprises a metallic housing 10 having a mounting groove 12 in the right-hand portion whereby the housing 10 can be attached to a transmission housing bracket 14. The housing 10 carries an O-ring seal 16 adapted to en- 3,226,497 Patented Dec. 28, 1965 gage the periphery of an aperture through the transmission housing, not shown. A drive shaft 18 is rotatably supported within the housing 10 and has a drive pinion 20 attached to the inner end thereof by a split ring 22. The drive pinion 20 is adapted to mesh with a suitable power takeoff within the vehicle transmission, and thus is rotated at a speed proportional to vehicle road speed.

The portion of the transmitter housing 10 to the right of the bracket 14 is disposed within the vehicle trans mission housing, and thus is exposed to transmission fluid. In order to prevent the leakage of transmission fluid along the shaft 18 into the converter components of the transmitter, two axially spaced lip-type oil seals 24 and 26 are disposed within the housing and engage the shaft 18. The space 28 between the seals 24 and 26 is filled with grease, and any oil leaking by the first seal 24 flows into the grease cavity 28 from which it can be drained through a side wall aperture 30. In this manner the outer seal 26 is not subjected to the static head of fluid in the transmission, and is lubricated by the grease within the cavity 28. This tandem seal arrangement virtually precludes leakage of transmission fluid into the cupshaped portion 32 of the transmitter housing containing the converter components.

The drive shaft 18, as seen in FIGURES 2 and 3, has a flat portion 34 extending through a radial slot 36 of a drive plate 38. The drive plate 38 has two axially extending fingers, or tangs, 40 and 42 which are diametrically opposed. The end of the drive shaft 18 seats in a recess 44 of a brush holder disc 46 composed of insulating material. The tangs 40 and 42 of the drive plate 38 are disposed in peripheral grooves 48 and 50, respectively, of the disc 46, cantilever spring reeds 52 and 54 being held in position by the tangs 40 and 42, respectively. The ends of the tangs 40 and 42 are crimped over the front face of the disc 46 as clearly shown in FIGURES 2 and 4 so as to drivingly interconnect the disc 46 with the shaft 18.

The housing 10 is adapted to be electrically grounded, and the ground connection between the spring reeds 52 and 54 is completed through the fingers 40 and 42, respectively, of the drive plate 38 and the shaft 18 through a spring ring assembly 56, clearly shown in FIGURES 2 and 6. The spring assembly 56 engages the housing 10 and has a pair of leaf spring fingers 58 which wipe the shaft 18. The cantilever springs 52 and 54 carry diametrically opposed brushes 60 and 62, respectively.

The transmitter includes three additional brushes 64, 66 and 68 which are supported by a unitary cantilever spring assembly 70, composed of either beryllium copper or Phosphor bronze. The unitary cantilever spring assembly 70 is most clearly shown in FIGURE 4 from which it can be seen that it embodies three cantilever spring arms 72, 74 and 76 carrying the brushes 64, 66 and 68, respectively. The spring assembly 70 is attached to the brush holder disc 46 by means of dowels 7'8 and 80 projecting from the front face of the disc 46 through tapertures in the spring assembly 70, and peened over as clearly indicated in FIGURE 5.

The brushes 64 and 66 are also diametrically opposed, and the four brushes 60, 62, 64 and 66 are spaced mechanical degrees apart in accordance with the teachings of the aforementioned copending application filed of even date herewith. These four brushes are adapted to engage three commutator segments 82, 84 and 86 spaced mechanical degrees apart and each subtending an angle of 60. The commutator segments are carried by an insulating disc .88 which closes the cup-shaped recess 32 and is held in assembled relation therewith by stakes 90. The brush 6-8 engages a center mounted slip ring 92 carried by the disc 88, each of the commutator segments and the slip ring having terminal projections as shown in FIGURE 2. Accordingly, upon rotation of the brush holder relative to the stationary commutator, the direct current supplied between the slip ring 92 and the housing will be converted into double frequency three phase alternating current which can'be used to energize a synchronous receiver motor so as to indicate vehicle road speed.

While the embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A brush holder assembly for an electric transmitter comprising a housing with a cup-shaped recess, a drive shaft journalled in the housing, a disc of insulating material disposed within said recess and having a pair of axially extending peripheral grooves, a drive plate connected to said drive shaft having a pair of tangs disposed in the grooves of said disc for imparting rotation thereto,

a pair of cantilever springs, each cantilever spring having an inner end portion disposed in one of said peripheral grooves and retained therein by one of said tangs whereby said pair of cantilever springs are electrically interconnected by said drive plate, each cantilever spring carrying a brush at its outer end, and a unitary cantilever spring assembly attached to the front face of said disc having a plurality of cantilever spring arms, each of which carries a brush at its outer end.

2. A brush holder assembly for an electric transmitter comprising a housing with a cup-shaped recess, a commutator attached to said housing having a plurality of circumferentially spaced commutator segments and a center slip ring, a drive shaft rotatably journalled in the housing, a disc of insulating material having a pair of diametrical- 1y opposed axially extending peripheral grooves, a drive plate connected to said drive shaft and having a pair of diametrically opposed longitudinally extending tangs disposed in the grooves of said disc for imparting rotation thereto, a pair of cantilever springs having inner end portions clamped within the grooves of said disc by said tangs on said drive plate whereby said pair of cantilever springs are electrically interconnected by said drive plate, each cantilever spring carrying a brush :at its outer end engageable with said commutator segments, and a unitary cantilever spring assembly attached to the front face of said disc, said unitary cantilever spring assembly including three cantilever spring arms, each of which carries a brush at its outer end, two brushes of said unitary cantilever spring assembly being engageable with said commutator segments, and the third brush of said unitary cantilever spring assembly being engageable with said slip ring.

3. The brush holder set forth in claim 2 wherein said unitary cantilever spring assembly is attached to said insulating disc by a pair of dowels.

References Cited by the Examiner UNITED STATES PATENTS 880,7-05 3/1908 Woodbridge 321--49 1,493,636 5/ 1924 Kunkle 200-14 X 2,090,505 8/1937 Uhle 20011 2,752,435 6/1956 Kalmus et al. ZOO-26 2,990,459 6/ 1961 Stanbro et al 200--166 X 3,030,460 4/1962 Huetten et a1 20011 3,043,922 7/1962 Laviana et al. 20024 3,078,355 2/ 1963 Kugler 200166 X KATHLEEN H. CLAFFY, Primary Examiner.

FREDERICK M. STRADER, BERNARD A. GIL- HEANY, Examiners. 

1. A BRUSH HOLDER ASSEMBLY FOR AN ELECTRIC TRANSMITTER COMRPISING A HOUSING WITH A CUP-SHAPED RECESS, A DRIVE SHAFT JOURNALLED IN THE HOUSING, A DISC OF INSULATING MATERIAL DISPOSED WITHIN SAID RECESS AND HAVING A PAIR OF AXIALLY EXTENDING PERIPERAL GROOVES, A DRIVE PLATE CONNECTED TO SAID DRIVE SHAFT HAVING A PAIR OF TANGS DISPOSED IN THE GROOVES OF SAID DISC FOR IMPARTING ROTATION THERETO, A PAIR OF CANTILEVER SPRINGS, EACH CNATILEVER SPRING HAVING AN INNER END PORTION DISPOSED IN ONE OF SAID PERIPHERAL GROOVES AND RETAINED THEREIN BY ONE OF SAID TANGS WHEREBY SAID PAIR OF CANTILEVER SPRINGS ARE ELECTRICALLY INTERCONNECTED BY SAID DRIVE PLATE, EACH CANTILEVER SPRING CARRYING A BRUSH AT ITS OUTER END, AND A UNITARY CANTILEVER SPRING ASSEMBLY ATTACHED TO THE FRONT FACE OF SAID DIDC HAVING A PLURALITY OF CANTILEVER SPRING ARMS, EACH OF WHICH CARRIES A BRUSH AT ITS OUTER END. 